Putting 1 Foil Faced Ridig Board Under Attic Roof

Foil insulation is a radiant barrier and it works by.

Putting 1 foil faced ridig board under attic roof.

There s two ways you can go about with foam board insulation. We live in zone 5 suburb of chicago and are hopefully about to put rigid foam above the roof sheathing on just the northeast roof portion of our roof. My plan was to rip one inch strips of wood to put on the back of the roof decking then cut the polyiso board to fit in between the rafters leaving one inch gap for ventilation as well as a 1 4 inch gap on either side to seal after installation. Multiple layers of foam board may be required.

This is an even more dense and more expensive foam board insulation. Install ap foil faced foam boards between rafters directly against the bottom of the roof sheathing. The r value of the insulation must meet local building code requirements for unvented attics to prevent condensation. Select rigid foam insulation boards that are at least 1 2 inch less in thickness than the rafter space is deep if you plan to finish the attic as living space.

Foam insulation boards are the best material with which to work when undertaking a do it yourself project because foam. R panel is manufactured with a closed cell polyisocyanurate foam core bonded to fiberglass reinforced facers and designed for use over metal nailable and non nailable roof decks with a variety of membrane systems. Installing rigid foam insulation. I have 2x10 rafters.

Polyiso comes in several thicknesses and is used over house sheathing underneath siding or in attic spaces where its reflective properties are very effective. It provides an r value of 6 per inch of thickness and often comes foil faced to help reflect radiant heat. However foil faced iso panels are warranted as impermeable. Then a second layer of plywood sheathing and asphalt shingles following the steps explained in this article.

Foil insulation underlayment is recommended under a metal roof and in most cases the shiny side should be facing up but there s a catch. If you want to use them without creating a vapor barrier look for permeable iso panels faced with fiberglass. I have at my disposal four inch polyiso board with the foil facing. 4 of polyiso under 4 of eps all above the original roof sheathing.

Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. Installing foam insulation boards in the attic is no that hard and can save you money compared with professional installation.